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July 26, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
pepe is tasked with carefully measuring precisely one mole of aluminum. How should pepe go about completing this assignment?
Monday, January 11, 2016 by Ivan

chemistry
What is the percentage by mass of sodium (Na) in a formula unit of sodium hydrogen carbonate (NaHCO3)?
Monday, January 11, 2016 by juan

chemistry
If I wanted to make two solutions. In one I will mix Chemical A into 1 Liter of water. In the second I will mix Chemical B into 1 Liter of water. If I want my two solutions to be the same concentration they should contain the same number of PARTICLES. How can I make sure both ...
Monday, January 11, 2016 by anthony

Chemistry
Part 1 : a.) How many grams of Hydrogen will be contained in a 100.000 g sample of magnesium hydroxide.? c.) How many grams of nitrogen will be contained in a 120.0 g sample of calcium cyanide? ________________________________________​ Part 3: d.) How many grams of ...
Monday, January 11, 2016 by Amber Deana B.

Chemistry
I'm confused on how to do these. Please show and explain how to do these. Test/quiz may be tomorrow. Pop Quiz!!! How do you calculate the percent composition of each of the following compounds? a.) Magnesium hydroxide b.) Calcium Cyanide c.) Nickel (ii) Iodide d.0 Copper (...
Monday, January 11, 2016 by Amanda

Chemistry
Why does magnesium burn with a white flame? What does it say about the electron transitions that take place?
Monday, January 11, 2016 by Anonymous

math/ chemistry
so I have this chemistry problem which involves math and basically I need to convert 62 g/mol into mol/L but I don't know how. like do you DIVIDE the g/mol by 1000 to convert g to L? and then how to you get the mol to become the numerator?
Monday, January 11, 2016 by kayla

Chemistry
One atmosphere of pressure will push a column of mercury to a height of 760 mm when the closs sectional area of the column is 1.00 cm.what would be the height of the column of mercury supported by the atmosphere if its cross sectional area were 0.500cm? How High would the ...
Monday, January 11, 2016 by gases laws and kinetic theory

Chemistry-Dr.Bob
You are at your cabin in the woods. Will you be able to take a hot bath tonight if only 0.1 lb of propane remains in the tank? Explain. My answer: No, I will not be able to take a hot bath. By making assumptions and approximations, I got... energy released for combustion is ...
Monday, January 11, 2016 by Sanaya

Chemistry-Dr.Bob
Why is gasoline (octane) better than diesal (cetane)?
Monday, January 11, 2016 by Sanaya

chemistry
A 20.00 g sample of metal is warmed to 165˚C in an oil bath. The sample is then transferred to a coffee cup calorimeter that contains 125.0 g of water at 5.0˚C. The final temperature of the water is 8.8˚C. mrtal water m=20g m=125g t1=165c t1=5 c=? t2=8.8 c...
Monday, January 11, 2016 by mariam

Chemistry
What is the chemical symbol for dihydrogen monoxide? I heard from the classmates and they laughed at each other. I can't understand!!
Monday, January 11, 2016 by Water-melon

chemistry
A flask containing 200 mL of solution is labeled 0.300 M CuBr2. A sample containing 0.0500 moles of Br− is added to the solution. What is the molarity of the Br− ion solution? Assume no volume change. a) 0.850 M b) 0.667 M c) 1.10 M d) 1.00 M e) 0.400 M
Monday, January 11, 2016 by bilawal

Chemistry
In what part of the electromagnetic spectrum would transition lines of n = 7 be expected to be found?
Monday, January 11, 2016 by Anonymous

Chemistry
Can a flame test and emission spectrum test be used to identify a mixture with two or three elements?
Sunday, January 10, 2016 by Anonymous

Chemistry
Why can't a single spectral line be used to identify an element?
Sunday, January 10, 2016 by Anonymous

Chemistry-Dr.Bob
Since most chemical reactions are conducted in containers open to the armisphere, why is the energy transfer associated with a chemical reaction generally expressed as the change in enthalpy? Is it because the enthalpy of reaction measures the change in energy of a chemical ...
Sunday, January 10, 2016 by Sanaya

chemistry
A lighter contains 3.59 g of butane. How many moles of butane are present at STP? Thoughts: So, correct me if I'm wrong however is it appropriate just to calculate its molar mass, and then use that molar mass and the given mass to figure out moles??
Sunday, January 10, 2016 by Gerry

Chemistry
In the lab, 5.8 L of methane gas is burned with excess oxygen gas at SATP. How much carbon dioxide gas is produced? **Based on the balanced chemical equation the ratio of methane gas to carbon dioxide is 1:1, this being said, does it make sense that as 5.8 L of methane gas is ...
Sunday, January 10, 2016 by Bob

chemistry
How many formula units are in 1.31 mg of hydrogen peroxide (H2O2)? Answer in units of formula units. For 508 g of butadiene (C4H6) calculate the number of moles. Answer in units of mol. Calculate the number of molecules. Answer in units of molec. 016 1.0
Sunday, January 10, 2016 by Erika

chemistry
How many molecules are in 24.0 g NO2? Answer in units of molec.
Sunday, January 10, 2016 by Erika

chemistry
How many molecules are in 0.0700 mol NH3? Answer in units of molec.
Sunday, January 10, 2016 by Erika

chemistry
How many molecules are contained in 1.30 mol O2? Answer in units of molec.
Sunday, January 10, 2016 by Erika

chemistry
How many grams do 6.2×1024 atoms of argon weigh? Answer in units of g.
Sunday, January 10, 2016 by Erika

Chemistry
Is this equation for acetic acid + sodium chloride balanced? C2H4O2 + NaCl ---> HCl + C2H3NaO2
Sunday, January 10, 2016 by Anonymous

chemistry
calculate the concentration of potassium in grams per liter after mixing 100ml of 0.250m and 200ml of 1.00m k2s04
Sunday, January 10, 2016 by Divao

chemistry
Mno4- + So3-2 = Mno2 + sO4-2 (in neutral solution,but H+ ions will appear in the final question) solve this redox reaction and give me the method also Thank you
Sunday, January 10, 2016 by taylor

Chemistry
Salts of barium, barium sulfate Particularly, When applied orally and because of its low solubility (Ksp = 1 x 10 ^ -10) Increase contrast for X-rays in medical diagnosis of the digestive system. Considering que Were reacted 7 × 10 -5 moles of CaCl2 with an equivalent ...
Saturday, January 9, 2016 by Igor

Chemistry
Salts of barium, barium sulfate Particularly, When applied orally and because of its low solubility (Ksp = 1 x 10 ^ -10) Increase contrast for X-rays in medical diagnosis of the digestive system. Considering que Were reacted ^ 7 × 10 -5 mol of CaCl2 with an equivalent ...
Saturday, January 9, 2016 by Igor

Chemistry
How much of a 50.0 grams sample of Uranium-238 would remain after 26 minutes IF the half-live is 13.0 minutes?? This question has stummed me and I can't do it, ugh.
Saturday, January 9, 2016 by Isbale

Chemistry-Dr.Bob
An unknown piece of metal weighing 100. g is heated to 90.0 degrees Celcius. It is dropped into 250 g of water at 20.0 degrees Celcius. When equilibrium is reached, the temperature of both the water and piece of metal is 29.0 degrees Celcius. Determine the specific heat of the...
Saturday, January 9, 2016 by Sanaya

chemistry
Is bp of para and meta and ortho isomer are same
Saturday, January 9, 2016 by debobrata

Chemistry
calculate the initial concentration of HCOONa you would add to 0.10M HCOOH to make a buffer with a pH of 4.00 [Ka (HCOOH) = 1.8 x 10^-4]
Saturday, January 9, 2016 by Christabel

chemistry
explain why metal oxides tend to be basic if the oxidation number of the metal is low and acidic if the oxidation number of the metal is high
Saturday, January 9, 2016 by Faye

Chemistry
100 mL 0.1 M sodium acetate solution is mixed with 50 mL 0.1 M acetic acid. If now 0.937 mL of 1 M sodium hydroxide is added to the buffer what is the change in pH? pKa (acetic acid) = 4.76
Saturday, January 9, 2016 by Jamie

Chemistry
reacting 3 mol C4H10 and 12 mol O2 will occur as a complete combustion, true or false
Saturday, January 9, 2016 by RN

Chemistry
The standard free energy of formation of nitric oxide, NO, at 1000. K (roughly the temperature in an automobile engine during ignition) is 77.5 kJ/mol. Calculate the equilibrium constant for the reaction
Saturday, January 9, 2016 by Anonymous

chemistry
55 gm laughng gas contains ---------gm N.
Saturday, January 9, 2016 by G.raju

chemistry
If 6.00g of carbon is heated in air, the mass of the product obtained could either be 22.0g or 14.6g depending on the amount of air present. Using calculations with what law will this be in accordance?
Saturday, January 9, 2016 by Divine phyavuh

Chemistry
20.0 mL of ethanol initially at 7.2 degrees Celsius is mixed with 31.7 mL of water initially at 28.9 degrees Celsius in an insulated beaker. Assuming no heat is lost, what is the final temp? I did not include the density, but I solved for mass, and have the SHC, for both. Don...
Friday, January 8, 2016 by Jennifer

chemistry
what is the total number of atoms in the compound (NH4)3PO4?
Friday, January 8, 2016 by Cayden

Chemistry
Will 100g of copper completely replace all the silver in 200g of silver nitrate
Friday, January 8, 2016 by T

Chemistry-Dr.Bob, I need you!!!!
You can mix 100.mL of 1.0 M HCl with 100 mL of 1.0 NaOH, both at 25 degree Celcius. The temperature of your calorimeter rises by 5.98 degree C, and its heat capacity is 100 J/degre C. How much energy is released per mol of H2O formed? My answer: 6x10^6 J per mol H2O I think we...
Friday, January 8, 2016 by Sanaya

Chemistry-Dr.Bob
You can mix 100.mL of 1.0 M HCl with 100 mL of 1.0 NaOH, both at 25 degree Celcius. The temperature of your calorimeter rises by 5.98 degree C, and its heat capacity is 100 J/degre C. How much energy is released per mol of H2O formed? My answer: 6x10^6 J per mol H2O
Friday, January 8, 2016 by Sanaya

chemistry
200cm3 of each of 0.1m of solutions of lead (ii) trioxonitrate (v) and hydrochloric acid were mixed. Assuming that lead (ii) chloride is completely insoluble, calculate the mass of lead (ii) chloride that will be precipitated.
Friday, January 8, 2016 by joshua

chemistry
What mass of NaHCO3 must be added to 100ml H2O to produce a solution with a pH of 10? K1(H2CO3)=4,6*10^-7 K2(H2CO3)=4,4*10^-11 -------- Help! Thank you
Thursday, January 7, 2016 by Sonia

basic chemistry
different ways to split a mixture of benzene into components using two phase system separation
Thursday, January 7, 2016 by shivani

Chemistry
Calculate pH and concentration of H2SO3, H2SO3- and SO32- in NaHSO3 c=0,05M. Ka1= 1,23*10^(-2) Ka2= 6,6*10^(-8) Results attached are: a) [H2SO3]= 1,04x10-4 M, [SO32-]=1,3x10-4 M, [HSO3-]= 0,05 M but i keep getting different numbers.
Thursday, January 7, 2016 by Anna

Chemistry
Compound X contains only carbon, hydrogen, nitrogen, and chlorine. When 1.00 g of X is dissolved in water and allowed to react with excess silver nitrate, AgNO3, all the chlorine in X reacts and 1.95 g of solid AgCl is formed. When 1.00 g of X undergoes complete combustion, 0....
Wednesday, January 6, 2016 by Anonymous

Chemistry
Compound X contains only carbon, hydrogen, nitrogen, and chlorine. When 1.00 g of X is dissolved in water and allowed to react with excess silver nitrate, AgNO3, all the chlorine in X reacts and 1.95 g of solid AgCl is formed. When 1.00 g of X undergoes complete combustion, 0....
Wednesday, January 6, 2016 by Sarah

Chemistry
Which molecule would be more soluble in water ? H----C=C---H or BeCl2
Wednesday, January 6, 2016 by Ali

Chemistry
Substances A and B, initially at different temperatures, come in contact with each other and reach thermal equilibrium. The mass of substance A is twice the mass of substance B. The specifi c heat capacity of substance B is twice the specifi c heat capacity of substance A. ...
Wednesday, January 6, 2016 by Anonymous

Chemistry
How do you calculate the number of moles and atoms of magnesium given the number o grams of magnesium chloride?
Wednesday, January 6, 2016 by Anonymous

Chemistry
Arrange the following compounds in order of increasing Boiling point: CH4, CHCl3, CCl4, CH3Cl
Wednesday, January 6, 2016 by Naaz

Chemistry
1. Convert 1.2 X 10^24 molecules of chlorine to grams. Ans: 70.67 gms
Wednesday, January 6, 2016 by Anonymous

Biology/Chemistry
Does anybody know how much 1 mole of acid should be diluted in order to mimic the pH of acid rain? I also need sources, but haven't been successful in any of my searches so far, thanks.
Wednesday, January 6, 2016 by Alice

Gratitude for my helper
Sir steve mrs reiny sir bobpursely sir damon ms sue..... Thank you very much you guyz have really help me alot today my result came out and i score 98 out of 100 in my maths exams aldo i am still shaking in my english but with the help of ms sue i always read english question ...
Wednesday, January 6, 2016 by Collins

Chemistry:normal notation plz help
Using the normal notation of quantum number find the element which has the following value of quantum number n=3 l=2 m=2 s=+1/2 (a):potassuim (b):nitrogen (c):sodium (d):scandium
Wednesday, January 6, 2016 by Collins

7th grade math
A biology class has 28 students. Four of the students transferred out to take chemistry. Find the percent of change in the number of students in the biology class. I got 86 percent change is that right? Thank you...My mom says it's 14.3 %
Tuesday, January 5, 2016 by Peggy

chemistry
I am wondering why H2S has only London Dispersion forces and not Hydrogen Bonding?
Monday, January 4, 2016 by David

chemistry
state what happens when chlorine is bubbled through Iron(II) sulphate solution .
Monday, January 4, 2016 by Anonymous

Chemistry
What is pH if 0.02M NaOH is added to buffer solution, consisting 0.4M aqueous NH3 & 0.3M NH4Cl(Kb=0.000018)
Sunday, January 3, 2016 by Solution

Chemistry
When 31 g of a metal at 88 ◦C is added to 46 g of water at 27 ◦C, the temperature of the water rises to 34 ◦C. What is the specific heat capacity of the metal? Assume no heat was lost to the surroundings. Answer in units of J / g ·◦C.
Sunday, January 3, 2016 by Amy

Chemistry
1.10 g of glucose was completely burnt in a copper calorimeter. The temperature of the water increased from 25.85 °C to 36.50 °C.
Sunday, January 3, 2016 by Khairavi

Chemistry
How do you find the formula for nitric acid?
Sunday, January 3, 2016 by Anonymous

Chemistry
What is the chemical formula and name when the following are added: 1. Na+1 Na-3 2. Na+1 Br-1 3. Na+1 O-2
Sunday, January 3, 2016 by Anonymous

chemistry
Based on mass spectrometer analysis of Uranium-235 and Lead-207, I have determined the age of a zircon to be 89.125 million years old. How many half-lives passed? What are the percentages of Uranium-235 and Lead-207?
Sunday, January 3, 2016 by HELP ME!! <3

Chemistry
The solubility of insoluble substances changes depending on the nature of the solution. Below are two solutions in which copper (II) hydroxide is dissolved; in each case, the solubility is not the same as it is in pure water. a. For each solution state whether the solubility ...
Sunday, January 3, 2016 by Marina

Chemistry
An iron nail with a mass of 0.750 g was dissolved in dilute sulfuric acid and diluted to 100.0 mL volume. A 10.0 mL aliquot of this solution was then titrated with standard 0.200 M potassium permanganate solution, according to the following equation: MnO4- + H+ +Fe2+ --> ...
Sunday, January 3, 2016 by Marina

chemistry
what is the advantage of using the indirect method over the direct method for calculating the enthalpy change of 2KHCO3 - K2CO3 + CO2 + H20
Sunday, January 3, 2016 by stephanie

chemistry
Explain the following statement. A saturated solution contains a mixture of silver chloride, AgCl and silver carbonate, Ag2CO3. An addition of hydrocloric acid will decrease the solubility of AgCl
Sunday, January 3, 2016 by oliver

chemistry
Explain the following statement. When aqueous ammonia is added to solution containing Pb2+ ions, a white precipitate is formed.
Sunday, January 3, 2016 by oliver

Chemistry
Q. How much of 80% alcohol should b mixed with 30ml of 95% alcohol in order to prepare 90% alcohol?
Saturday, January 2, 2016 by Vitthal

chemistry
why potassium permegnate is colourd
Saturday, January 2, 2016 by aiman

chemistry
why we add acid to the standardization of sodium thiosulphate solution?
Saturday, January 2, 2016 by aiman

chemistry
why we not use HNO3 and HCl in iodometry
Saturday, January 2, 2016 by aiman

chemistry
Please help me!!! Write a balanced chemical equation for oxidation-reduction reaction of fluorene
Saturday, January 2, 2016 by Yusuf

chemistry
A 90walt emersion heater is used to supply energy for 5min. The energy supplied is used to completely melt 160g of a solid at it's melting point.calculate the S.L.H of fusion of the solid.
Friday, January 1, 2016 by abdullahi yusuf

chemistry
an ionic bond will most likely form between elements from group_ a/2and3 , b/2and6 , c/3and4 , d/4and5 ,e/5and6
Friday, January 1, 2016 by barbie

Chemistry
What is the chemical formula and name for: Na+1 and Na-3?
Friday, January 1, 2016 by Anonymous

Science - Chemistry
If vapour pressure of water is 17.5 torr at 20C, what is the water vapour pressure inside a bottle of 100 proof whiskey? 100 proof = 50% ethanol Total volume = 1 L Mass of ethanol = 394.5g Mass of water = 500g Density of ethanol = 0.789g/mL Moles of ethanol = 8.58 mol Moles of...
Wednesday, December 30, 2015 by Sara

Chemistry
Are there any disadvantages of a mass spectrometer
Tuesday, December 29, 2015 by Kwadwo Ansah

chemistry
report on the preparation of 0.004M stock solution of ethanoic acid
Tuesday, December 29, 2015 by mercy

Chemistry
An experiment calls for 100ml of 0.1M copper(II) sulfate solution. Write a step-by-step procedure for a science teacher to make 100ml of 5M stock solution and the required diluted solution.
Tuesday, December 29, 2015 by Esther

Chemistry
How do you separate a mixture of iron fillings and sulphur powder by use of methylbenzene
Tuesday, December 29, 2015 by Ian

maths physics chemistry
State the principle on which each of the following is based. (a) the equation of continuity, Av = constant (b) the Bernoulli equation
Tuesday, December 29, 2015 by Joseph

chemistry
The solubility of a compound in water is 6.8g/100ml at 25°C. Calculate the amount of water required to crystallise 10g of the compound. If the pure compound is collected at 25°C what is the maximum possible yield percent?
Tuesday, December 29, 2015 by Amas

chemistry
How many grams of SrCl2 is required to prepare 1 molar solution of it,
Tuesday, December 29, 2015 by anitha

chemistry, physics please help
Calculate the molar enthalpy of solidification when 10.00KJ of energy are lost as 30.00g water are frozen at 0*C. i divided 30/18.02 =1.664 mol then, divided 10KJ/1.664mol =6.010 KJ/mol Am i correct? Thank you!
Monday, December 28, 2015 by miyabi

chemistry
A 250.0mL sample of 0.0012M Pb(No3)2 (aq) is mixed with 150.0mL of 0.0640M Na (aq) should precipitation of PbI2 (s) ,Ksp=7.1¡Á10^-9, occur?
Monday, December 28, 2015 by alfred

chemistry
If the titration of a 30.0 mL sample of sulfuric acid requires 27.65 mL of 0.090 M sodium hydroxide, what is the molarity of the acid? H2SO4(aq)+2NaOH(aq)→Na2SO4(aq)+2H2​O(l)
Sunday, December 27, 2015 by lisa

Chemistry
the pH of a solution is 10 and other is 12 when equal volumes of these low are mixed the pH of the resulting solution is?
Sunday, December 27, 2015 by Pandu

Chemistry
Reaction of gaseous fluorine with compound x yields a single product y, whose mass percent composition is 61.7% F and 38.3%Cl. (a) What is a probable molecular formula for product Y, and what is a probable molecular formula for X? (b) Draw an electron-dot structure for Y, and ...
Saturday, December 26, 2015 by Malan

Chemistry
Enter the formulae of the products and give their states. Type your answer using the format Na2SO4(aq) for Na2SO4(aq). Do not balance the equation. If there are no products, enter "none". ZnCO3(s) + heat ---> I know it's a decomposition reaction, so I thought ...
Thursday, December 24, 2015 by Anna

chemistry
Report the preparation of stock solution of 0.04M of sulphoric acid
Thursday, December 24, 2015 by edache

Chemistry
Based on mass spectrometer analysis of Uranium-235 and Lead-207, I have determined the age of a zircon to be 89.125 million years old. How many half-lives passed? What are the percentages of Uranium-235 and Lead-207?
Tuesday, December 22, 2015 by Anonymous

Chemistry
The carbon buried in a peat bed has about 12.5% of the Carbon-14 of modern wood. What is the age of the peat bed? Explain?
Tuesday, December 22, 2015 by Anonymous

chemistry
Which among hydride, methyl or phenyl shift is the most preferred?
Tuesday, December 22, 2015 by Rajat

Chemistry
Take the reaction: NH3 + O2 ---> NO + H2O. In an experiment, 3.25 g of NH3 are allowed to react with 3.50 g of O2. Which reactant is the limiting reagent? You may either write the formula or the name of the limiting reactant.
Monday, December 21, 2015 by Ayame

Chemistry
How would you prepare the ff. solutions: 1. 45g NaCl/g H2O 2. 25% w/v NaCl Thank you in advance.
Monday, December 21, 2015 by JamesKim

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Homework Help: Science